Advanced Driver Assistance Systems are increasingly used in vehicles to provide assistance to drivers in areas such as braking, collision avoidance, and speed selection. Such systems may help to reduce driver workload, and may be useful in improving safety, vehicle operating efficiency, driver comfort and/or fuel efficiency.
Operation of an ADAS relies upon knowledge of the road ahead, and its properties. For example, the ADAS may take into account factors such as the curvature or gradient of a section of the road ahead in order to determine a suitable speed for traversing the section, and may then, for example, control the braking subsystems of the vehicle in order to implement the determined speed. Typically a subsystem of the ADAS, which may be known as an ADAS horizon provider subsystem, communicates with ADAS applications of a vehicle network over a vehicle bus, such as a Controller Area Network (CAN) bus, in order to control vehicle subsystems. Different ADAS applications may control different respective vehicle subsystems in accordance with the information received from the ADAS horizon provider over the vehicle bus. For example, there may be ADAS applications in respect of braking, suspension, etc. The ADAS horizon provider subsystem provides ADAS horizon information which may be used by the ADAS applications associated with given vehicle subsystems to provide control of the respective vehicle subsystems using the ADAS horizon data.
One aspect of the operation of the ADAS horizon provider subsystem relates to the generation of a suitable ADAS “horizon” for communication over the vehicle bus to the vehicle subsystems. The ADAS horizon comprises digital map information about a portion of the road network ahead, which is used by the ADAS applications to implement ADAS functionality with respect to the vehicle subsystems. Determination of the ADAS horizon involves predicting the path or paths that the vehicle may travel in the immediate future, to ensure that the necessary data is transmitted over the vehicle bus to allow implementation of ADAS functions by the vehicle subsystems as the vehicle travels.
The ADAS horizon may include information about the course of a road ahead, and associated attributes of the road, such as curvature, gradient, etc which may be used by ADAS applications of the vehicle to implement ADAS control of the vehicle subsystems. ADAS applications associated with different vehicle systems may filter the provided ADAS horizon data to extract the information required for controlling their relevant subsystem. For example, road curvature data may be extracted for use in controlling the braking system.
When determining a suitable portion of the road network ahead for inclusion in the ADAS horizon, it is necessary to balance providing sufficient data to ensure that ADAS functionality may be adequately implemented by vehicle systems while avoiding overloading the vehicle ADAS applications associated with the vehicle systems. The prediction of the path or paths that the vehicle may be expected to travel in the near future is therefore fundamental to the generation of a suitable ADAS horizon. The determination of a suitable ADAS horizon may involve certain challenges, for example depending upon whether the vehicle is following a pre-calculated route or not, and to accommodate potential deviations of a vehicle from a pre-calculated route. For example, in a simple case, the ADAS horizon may comprise data relating only to the road currently being traversed up to a predetermined distance from a current position. However, in such situations, the ADAS applications may be left “blind” for a time if the driver deviates from the road currently being traversed until a new ADAS horizon can be generated in relation to the newly traversed road section.
The Applicant has realised that there is a need for improved methods and systems for generating a horizon for use by an ADAS, and in particular, for predicting a path or paths that a vehicle may travel in the immediate future when generating an ADAS horizon.